In order to understand the nature of the gold(III) catalyzed dealkylations of methyl cobalamin, monomethylgold(III) compounds are being synthesized and studied. In arthritis therapy, gold(I) issnormally introduced into the body as a mercaptide complex, and gold is transported as a mercaptide complex. A series of gold(I) mercaptide complexes has been synthesized, and these are being characterized by chemical and spectroscopic techniques. Raman difference spectrophotometry (RDS) is a powerful tool for studying the binding of heavy metals to biological molecules in dilute aqueous solution. RDS is being used to determine the sites at which the probe ion CH3Hg ion binds to polynucleotides. This work is being extended to the bifunctional metal complexes which possess antitumor activity.